The bones are hollow and make the bird light and he can fly by flapping his wings.
the flapping of the wings propel the bird forwards
flapping
Thrust and lift
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By flapping it wings causing enough momentum for the bird to fly.
Eagle
No, this is physically impossible unless you are a bird.
By flapping it's wings like every other bird on the planet.
condor
An albatross can glide over a thousand miles without flapping its wings.
Iron Birds